Nuclear propulsion

By Nick Touran

When nuclear energy was first harnessed, the US Navy became extremely
interested in using it to power its fleet of submarines. Nuclear energy
is perfect for submarines because:

It’s very energy-dense, so a sub could be underway at high power for decades without
refueling.

It doesn’t require oxygen for combustion, so there’s no need to surface frequently, and
the engine and sailors don’t compete for air.

A nuclear-powered submarine has a critical nuclear chain reaction going
on near the center of the submarine. This boils water, which then
goes through a turbine. The turbine is hooked up to a big drive-shaft
that is hooked to a propeller on the back of the submarine. There are
auxiliary turbines as well that are hooked up to electric generators
to make electricity for the systems on the sub.

There are two main types of nuclear-powered submarines:

Ballistic missile submarines

Ballistic missile subs (AKA “boomers”) are not only
powered by a nuclear reactor, but they also carry a large amount
of missiles with thermonuclear weapons for warheads. These submarines
are supposed to just prowl around in unknown locations in the sea as a
deterrent, so if someone nukes you, you can nuke them back from these subs
and they’ll never be able to prevent you from doing so because you could
be anywhere. In essence, these prevent people from nuking other people.

Fast attack submarines

Fast attack subs are the hunter-killers of the sea.
Their job is to hunt down and destroy other submarines or vessels.
They’re fast and typically armed with things like Tomahawk missiles,
and MK-48 torpedoes.

Nuclear-powered surface ships

Nuclear propulsion worked so well for submarines that a few other
vessels got nuclear engines instead of conventional
diesels. Most notably, vessels like the Gerald R. Ford-class
aircraft carriers have a few nuclear reactors powering them.
The US Navy has had nuclear-powered cruisers as well, but
does not have any now.

Civilian nuclear propulsion

Russia operates a fleet of nuclear-powered icebreakers.
A few nuclear merchant ships operated but none are in commission
today. They would be an excellent way to reduce the emissions
from the huge amount of international shipping that’s ongoing today.

Did you know? The NS
Savannah was a nuclear-powered
cargo ship that operated between 1962 and 1972. It’s deactivated now and
moored at Pier 13 in Baltimore.

Relation to commercial nuclear power

Commercial nuclear power plants evolved from naval nuclear reactors,
and the main designs in use today making electricity (PWRs and BWRs)
are direct decedents of naval reactors. Water coolant is really
nice at sea because there’s a lot of cooling water. A lot of
plant operators learned how to run nuclear reactors in the Navy.

Besides ships, what else has been propelled by nuclear energy?

Nuclear propulsion is well-suited for space travel and rockets, so that’s
under development. The Russians did have some nuclear-powered tanks.
Before intercontinnental ballistic missiles were developed, the US Air
Force worked a lot on the Aircraft Nuclear Propulsion project to make
a nuclear-powered long-range airplane. Various test reactors like HTRE-3
pictured here were operated
in this project but no plane ever actually flew, so far, on nuclear power.

The only nuclear-powered cars you’re likely to ever see are electric ones
charged by nearby nuclear power plants.